Sixty Meter Operation with Modified Radios The following pages document the results of 6-meter transmitter performance on a group of transceivers that have been modified to enable operation on the sixty-meter band. 1 This document was prepared to provide more information as to the issues that bear on proper 6-meter operation. It should be emphasized that it is the responsibility of each operator to ensure that his or her operating complies with the rules (for more information, refer to the "6-Meter FAQ" on the ARRL's web page at http://www.arrl.org/fandes/field/regulations/faq.html). Note that while most of the group of transceivers tested here are Kenwoods, this is strictly due to the selection of radios that were available at the time of the test. The specific models tested were as follows: ICOM IC-751 Kenwood TS-5 Kenwood TS-57 Kenwood TS-85 Kenwood TS-94 SGC SG-22ADSP Yaesu FT-897 All transceivers were tested on 5.335 MHz, in USB mode, with applied audio sufficient to produce 5 W PEP. 2 The tests performed on these transceivers were as follows: Spectral Purity Transmit Intermodulation Distortion Transmit Frequency Response using a swept audio input Transmit Frequency Response using pre-recorded female voices Transmit Frequency Response using pre-recorded male voices Miscellaneous Transmit Frequency tests In addition to the tests mentioned above, the Lab's Kenwood TS-95 was tested for Transmit Frequency Response on a frequency of 3.9 MHz in USB mode. Spectral Purity: For the Spectral Purity test, a 1 khz tone was supplied to the transceiver's microphone input, and the level of the audio was adjusted for 5 W PEP output. 2 Spectral Purity Test Results: Transceiver Worst-case spurious Transceiver Worst-case spurious ICOM IC-751 59 dbc Kenwood TS-85 56 dbc Kenwood TS-5 49 dbc Kenwood TS-94 45 dbc Kenwood TS-57 59 dbc SGC SG-22ADSP 48 dbc Yaesu FT-897 63 dbc
Transmit Intermodulation Distortion (IMD): For the Transmit IMD Test, the Lab's Audio Two-Tone Generator was connected to the transceiver microphone input and the controls of the generator were adjusted to produce 5W PEP with equal power in both tones (tone frequencies are 7 and 19 Hz). The spectral output is shown in the plots that follow. The additional "step" line on the graphs is the emissions limit for transceivers that are subject to type acceptance on the HF bands (47 CFR Part 2). While these limits are not a requirement for Amateur Radio transceivers for HF (which are not subject to type acceptance), they indicate the type of restrictions imposed on other services using this spectrum, including the primary users of the allocation at 6 meters. 8 6 4 2 2 4 6 8 1 ICOM IC-751A 5.33 MHz, Transmit IMD, 5 W I:\PRODREV\TESTS\6METERS\IC751\IC751I6.TXT 8 6 4 2 2 4 6 8 1 Kenwood TS-57S 5.33 MHz, Transmit IMD, 5 W I:\PRODREV\TESTS\6METERS\TS57\TS57I6.TXT 8 6 4 2 2 4 6 8 1 TS-5 5.33 MHz, Transmit IMD, 5 W I:\PRODREV\TESTS\6METERS\TS5\TS5I6.TXT 8 6 4 2 2 4 6 8 1 Kenwood TS-85 5.33 MHz, Transmit IMD, 5 W I:\PRODREV\TESTS\6METERS\TS85\TS85I6.TXT
8 6 4 2 2 4 6 8 1 ts94 5.33 MHz, Transmit IMD, 5 W I:\PRODREV\TESTS\6METERS\TS94\TS94I6.TXT 8 6 4 2 2 4 6 8 1 SGC SG-22ADSP 5.33 MHz, Transmit IMD, 2 W I:\PRODREV\TESTS\6METERS\SGC22\SGC2I6.TXT 8 6 4 2 2 4 6 8 1 Yaesu FT-897 5.33 MHz, Transmit IMD, 5 W I:\PRODREV\TESTS\6METERS\FT897\FT897I6.TXT
Transmit Frequency Response: A. Using a swept audio input. This test indicates the passband response of the transmitter under test. A constant level audio generator was connected to the transmitter's microphone input and the level was adjusted for 5W PEP at the point of maximum audio response. The attenuated transmitter output was connected to a spectrum analyzer, set to hold the RF peak for each frequency, accumulating the indicated response curve by repetitive spectral sweeps while manually changing the frequency of the audio generator. The definition of bandwidth in the FCC Rules Part 97.3(a)(8) is "the width of a frequency band outside of which the mean power of the transmitted signal is attenuated at least 26 db below the mean power of the transmitted signal within the band," but this does not mean that the bandwidth can be inferred from the points 26 db below the peak response shown. For a discussion of this issue see Note 3, which was provided by Ed Hare, W1RFI. On the plots shown, the heavy vertical lines indicate the boundaries of each 2.8 khz channel. The frequency offset shown is the offset relative to the suppressed carrier. 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. ICOM IC-751A 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\IC751\IC751U6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. TS-5 Swept Audio generator 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS5\TS5U6.TXT
1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-57S 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS57\TS57U6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-85 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS85\TS85U6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-94 Swept with Audio Gen 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS94\TS94U6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. SGC SG-22ADSP 5.33 MHz, USB, 2 W I:\PRODREV\TESTS\6METERS\SGC22\SGC2U6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Yaesu FT-897 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\FT897\FT897U6.TXT
B. Transmit frequency response using pre-recorded female voices. This test was performed with the same setup as with the audio response test shown above, except that the audio source was a recording of several female voices. The peak response shown in these graphs represents the effect of cumulative speech; see Note 3 for more information on how this relates to average speech power. 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. ICOM IC-751A female voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\IC751\IC751F6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-5 female voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS5\TS5F6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-57S Female voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS57\TS57F6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-85 female voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS85\TS85F6.TXT
1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-94 female voices 5.33 MHz, Transmit IMD, 5 W I:\PRODREV\TESTS\6METERS\TS94\TS94F6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. SGC SG-22ADSP female voices 5.33 MHz, USB, 2 W I:\PRODREV\TESTS\6METERS\SGC22\SGC2F6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Yaesu FT-897 female voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\FT897\FT897F6.TXT C. Transmit frequency response using pre-recorded male voices. This test was performed with the same setup as with the audio response test shown above, except that the audio source was a recording of several male voices. The peak response shown in these graphs represents the effect of cumulative speech; see Note 3 for more information on how this relates to average speech power.
1..5..5 1. 1.5 2. 2.5 3. 3.5 4. ICOM IC-751A male voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\IC751\IC751M6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-5 male voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS5\TS5M6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-57S male voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS57\TS57M6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-85 male voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS85\TS85M6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-94 male voices 5.33 MHz, Transmit IMD, 5 W I:\PRODREV\TESTS\6METERS\TS94\TS94M6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. SGC SG-22ADSP male voices 5.33 MHz, USB, 2 W I:\PRODREV\TESTS\6METERS\SGC22\SGC2M6.TXT
1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Yaesu FT-897 male voices 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\FT897\FT897M6.TXT Miscellaneous Transmit Frequency Response Tests In addition to the above swept-audio and voice response tests, a couple of the transceivers were tested for audio response with either the processor on, or some sort of audio enhancement enabled. Specifically, the effect of the "High Boost" feature of the Kenwood TS-85 was examined using a swept-audio input, and again using a voice input (in this case, the male voices recording was used). 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-85 high boost 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS85\TS85H6.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-85 male voices w/ high boost 5.33 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS85\TS85MH6.TXT On the Kenwood TS-95 (an unmodified transceiver), several tests were performed on 3.9 MHz in USB (so as to match the filter shape that would be observed on 5.3 MHz). The first plot of this group is the swept audio response of the transceiver. The second plot is the response to voice input (both male and female voices were used for this test). The third plot is the response of a male voice with the processor enabled.
1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-95 3.9 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS95\TS95U8.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-95 voices male and female 3.9 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS95\TS95V8.TXT 1..5..5 1. 1.5 2. 2.5 3. 3.5 4. Kenwood TS-95 voices w/processor 3.9 MHz, USB, 5 W I:\PRODREV\TESTS\6METERS\TS95\TS95P8.TXT
Notes: 1. These modifications are generally not endorsed by the transceiver manufacturers. Alinco, ICOM, Kenwood and Yaesu have all stated that they do not offer information on modifications to existing products to enable transmitting on the 6-meter band (apart from information supplied to MARS licensees). SGC has published modification information for their SG-22 model on their web page at http://www.sgcworld.com/newsletter/jul3/6meterops.html 2. The SGC SG-22 was adjusted for an output of 2 W PEP for all tests. 3. The Part 97 rules define bandwidth as follows: Sec. 97.3(a)(8) Bandwidth. The width of a frequency band outside of which the mean power of the transmitted signal is attenuated at least 26 db below the mean power of the transmitted signal within the band. However, this does not refer to the 26 db points on a spectral graph! Bandwidth is the frequency range outside which all of the other energy transmitted has a total power that is 26 db less than the signal transmitted inside that frequency range. So a whole bunch of intermodulation distortion that was 27 db below the level inside the communications channel wouldn't be legal because all those 27 db signals would add up to be more than 26 db. One also must consider "mean power." In a voice transmission, those "S" and "T" sounds with significant higher-frequency components may be fairly strong, but they don't occur very often, so their mean power is actually fairly low compared to the lower-frequency energy in the "main" passband of the communications channel. Observe the passband responses shown in this report, noting the differences in the swept audio response and the voice responses. If an analysis of the average power was done, it would indicate a bandwidth that was even less than that seen with the peak-hold function on the spectrum analyzer. Last, but not least, in addition to the requirement to have our bandwidth <28 Hz, centered on the channel, even our out-of-band emissions are below that limit, if they cause harmful interference to the adjacent-channel users, we have a responsibility to correct the harmful interference.